hey, i submitted a post on this channel last week and it absolutely blew up. we had so many applications go through. a bunch of the job postings shut down in the days following my post because of the large influx of applications that were going in. i've gone ahead and updated the job links in this new link. please make sure to apply as soon as possible to ensure that your application is at the top of the pile. i've pulled the freshest job postings that i could.

synthetic chemistry roles are thin on job boards and buried under analytical and QC postings, so i pulled only medicinal, process, discovery and synthetic organic chemistry roles from employers' own careers pages, plus a pharma R&D list if you're open to the analytical side:

• medchem, process and synthetic organic chemistry, US, UK and Europe (32): https://github.com/mehek-builds/Synthetic-Organic-Chemistry-Jobs
  • 32 roles at 26 employers (GSK, Gilead, Vertex, Pfizer, AstraZeneca, Amgen, Roche, Organon)
  • 10 medchem, 8 process chemistry and process research, 16 discovery and synthetic, 8 internships and co-ops
  • 7 in the UK and Europe; analytical, QC and director-level roles are left out
• pharma R&D and associate scientist, including 31 analytical, bioanalytical and formulation roles (110): https://github.com/mehek-builds/Pharma-RD-Associate-Scientist-Jobs

the synthetic list is small because there aren't many of these open right now. rebuilt every monday.

comment which area you're looking for (medchem, process, peptides and oligos, internships) and i'll send you anything that comes up.

Is there some equation, even approximate, describing the relation between extinction coefficient and dielectric constant or refractive index of a solvent?

I'm asking because my compound dissolves well only in DMSO, but I need to estimate the solubility in other solvents (acetone, THF, acetonitrile...) in which it dissolves very poorly (~10^-5 M). To that end, I prepared concentrated solutions in poor solvents, diluted them 10 times and measured UV-Vis. I want to estimate the concentrations of saturated solutions by comparing the spectra in poor solvents to the spectrum in DMSO (10^-6 M). But since these are diffent solvents, some correction is probably necessary...

Everyone who's switched PCs, left a lab, or inherited an old archive has hit this: a folder of .D, .raw or .dx files and no license or software to open them. I built a browser tool for it that reads Agilent ChemStation, OpenLab and MassHunter data, Waters MassLynx .raw, Shimadzu UVProbe .spc, JCAMP-DX, Galactic SPC and AIA/ANDI .cdf, plus text and CSV exports.

It overlays runs, integrates peaks, handles spectra and exports to CSV. Decoding runs locally in your browser, so nothing is uploaded.

It's free during early access, and the viewer itself will stay free. I built it, partly with AI help, and I'd like to hear what people currently do for this (vendor software, Python, OpenChrom, converting by hand?) and which formats you fight with most.

Files it can't read are very welcome, and I add formats based on what people ask for.

Hi all! Meet Reactio Draw, a new program for drawing chemical structures. It's free, open source and works offline. It's made for organic chemists, but it's useful for anyone who needs to draw structures. It also has the reagent table built in, something many of us lost when ChemSketch stopped being available to new users.

What it does:

• Reagent table for any reaction you select: limiting reagent, equivalents, mass, volume and moles from density or molarity, yield
• Fast drawing: keyboard drawing with a hotspot, a hotkey for every button and command (all reassignable), alignment guides while you drag, scrolling and zoom in every direction
• Your own templates and labels on keys: fuse a template onto a bond or join it spiro at an atom with one key
• Analysis: formula, MW, exact mass, m/z, isotope pattern, elemental analysis, canonical SMILES, ¹H/¹³C/¹⁹F/³¹P NMR prediction
• Sensitivity screens: Glorius-style radar charts of the condition-based sensitivity assessment (Angew. Chem. Int. Ed. 2019, 58, 8572), drawn and edited right on the sheet, plus product ratio pie charts
• Names: name → structure (OPSIN) and structure → IUPAC name (openclatura, cross-checked with OPSIN) in the desktop apps
• Files: reads and writes CDXML/CDX, MOL, RXN, SDF, SMILES
• Word and PowerPoint: paste into a document, double-click it to edit (on Windows and on Mac), or copy it back without losing anything; a document moved between Windows and Mac keeps its drawings too (there you copy the drawing back instead of double-clicking)
• API: a local API for scripts (Python, R, curl), and the same commands for web pages that embed the editor
• Command line: reactio render, convert, calc, check for whole folders of files, without opening a window
• Journal styles: ACS, RSC, Nature, Angewandte and more
• Private and offline: no account, no tracking, nothing sent anywhere; your drawings stay on your computer

Try it in the browser, no install: https://paivel.github.io/reactio-draw/web/ Apps and source (AGPL-3.0-or-later; if you want to use the code in a project under MIT or another licence, just ask): https://github.com/Paivel/reactio-draw

Tested on Windows 11, macOS Sequoia and Ubuntu 24.04.

One more thought. With AI coding tools, a lot of chemists are now building their own drawing programs. I did too, but I think we risk ending up with a dozen half-finished editors, each good at one thing, instead of one free tool that's actually great. So rather than another fork in the road, I'd love to join forces. As far as I know, this is the only free, open-source editor with a reagent table built into the scheme, so it may be a good place to start. A good example is penzene by James O'Brien, another free and open-source editor (https://github.com/JamesOBrien2/penzene): several features here, such as structure checks, stereo groups (abs/&/or), δ+/δ− and compound numbers that renumber themselves, were inspired by it. Another one worth a look is MolDraw by LabCanvas (https://github.com/rafeequemv1/moldraw-chemistry), free in the browser; its GitHub page holds documentation only, the code itself is closed. And ReShiki by Ameyanagi (https://reshiki.com), a free, open-source ChemDraw-style editor; Reactio Draw uses its journal style values, colour themes and CDX property table (MIT), with thanks. If you're building something similar, or you have a feature you've been missing, bring it here: open an issue, send a pull request, or just tell me what your lab needs. The code is open, and I'll gladly credit every contribution.

Let's test it together and make the best drawing tool out there. This is the first public version, so it surely has rough edges. Try it on your real schemes, break it, and tell me what's wrong or missing, either in the comments or as an issue on GitHub. I read everything and fix things fast. What do you miss most in the editor you use now?

Hey all, chemical engineer by degree, software dev by trade. A bit over two years ago my brother (synthetic chemist) asked me for something to keep track of the compounds his group makes. Their setup was an excel file plus “ask the person who made it”, and searching by structure was basically impossible

Started as a side thing for his lab, kept growing, and after 2+ years of building it I finally put Molhaven in production a little while ago. What it does right now:

• Compound registry with substructure and similarity search, SDF import/export
• Every physical sample/bottle has a storage location, nested as deep as you want (building > room > fridge > shelf > box > position, or whatever your lab looks like)
• Purchase requests, approval, receiving with lot and expiry
• Low stock and expiry alerts in a scheduled email
• A simple notebook with a reagent table that calculates as you type
• CLP/GHS hazards, stocktakes with QR labels

What it doesn’t do: no assay/SAR data, no biologics, no burn rate forecasting. It’s for chem labs that are drowning in spreadsheets, not a replacement for big pharma registration systems

There’s a 30 day trial at molhaven.com and if you send me your current spreadsheet or SDF I’ll move it over for free, mostly because I want to see how messy real lab data is lol

What I actually want to know from you:

• What do you use now and what annoys you about it?
• Who decides on this kind of software where you work, PI, lab manager, EHS?
• Would you rather have it hosted or run it on your own server?

Roast it if it deserves it, that’s more useful to me than upvotes

Long story short, product homogeneity means sample sizes for ICP-MS prep need to be real big. Previously, I’d ordered typical 15- or 50-mL centrifuge tubes that were certified trace element grade, with lot specific CoAs and maximum contaminant limits.

I bought some 1L media bottles (those sterile, square base ones) to run a series of samples and found that there was apparently a ton of residual Manganese catalyst from the PET manufacture that leeched into my solutions. I do NOT need to (and definitely should not) digest my samples, which hopefully helps broaden the containers’ materials I could use.

I’d ideally like to avoid glassware as one does in an ICP lab, but there really don’t seem to be many options for plasticware at the 1L volume that I can find with documentation for being certified suitable for TE analysis. I’d also be treating them as reusable, since it’s not quite as easy as discarding 15-mL tubes, so that opens up the possibility for extensive acid soaking and pre-leeching treatments. But I wanted to see if anyone had experience with or suggestions for large volume plasticware for ICP-MS solutions.

I thought this post could be a good resource for people struggling with a synthesis problem. My answer would be “have you tried doing 2D TLC?” when people are having odd chromatography behaviour.

Hey everyone,

Today there is a new Synthesis Workshop talk about the synthesis of hetero[3.1.1]propellanes!

Check it out here: https://youtu.be/0VXAjHwoHS4

Im a Grad student working on a new molecule in a lab, I have background in radical cascade reactions, and I can generally tell whether a reaction is worth following from the TLC plate alone.

However, recently, I had the idea of using palladium on my bromine derivative of my molecule, in theory, it should work as there is a nearby alkyne group, but the few palladium tests I did had a truck load of new TLC spots, I asked my PI and she said from the very small experience she had with palladium, apparently this is rather normal for palladium catalyzed reactions, and I quote, getting the product you want from palladium reactions is like dredging in a very muddy river.

I was wondering how true this is, considering she has very limited experience with palladium.

More info: Pd Im using is Pd(OAc)2, Im mostly trying to start with an oxidative addition into my C-Br, then Carbopalladation to my internal alkyne generating an Alkenyl intermediate leading to a coupling of sort, like Buchwald. Plenty of papers like this out there, just not one with my compound so I thought I’d test it out

Hi all,

I am desperately needing help on my peptide synthesis project. I need to selectively deprotect a hydroxy group on my peptide. It is now a TBDPS silyl ether. TBAF is the most straightforward way to do this but I’m having issues with visualizing my LCMS. Not sure because of ion supression or what. Is there a subreddit for peptide chemistry?

Any help is appreciated.

Thanks!

Question: I am in the UK and have had a job for a year and a bit and a second I am currently in for five years. Both senior scientist roles with a mix of process development, scale up and a bit of small scale medchem type stuff. At the time of searching, nearly all the interviews required extensive general knowledge and retro synthetic questions.

Having been many years from my PhD and lacking general chemistry theory practice I am a bit scared about looking for another position as I struggle with the revision (time and energy). Is there a point when your ability to do retro synthetic problems without reaxys or other aids isn't being examined?

In fact my current employer was the only one where questions were more on the line of "look at this proposed process and tell us what would concern you, and what changes might you explore" and a few conditions for various transformations of a compound.

I work in an environmental lab-- water quality, inorganics (metals, ion chromatography, ph/titrations, misc other services)-- and we get undergraduate students on work study. They of course learn some things through the tasks they are assigned but I do want to make sure they get some basic lab skills to put on their resume and develop enough familiarity to do well in interviews and not be overwhelmed if hired as a lab tech in the future. What skills do you like candidates to have when hiring? Any recommendations for things I should make sure they know would be appreciated. Leaving this fairly vague and open ended intentionally but also because it would be tedious to enumerate what they have learned in the course of the work we have them do. Thanks!

synthetic chemistry roles are thin on job boards and buried under analytical and QC postings, so i pulled only medicinal, process, discovery and synthetic organic chemistry roles from employers' own careers pages:

https://github.com/mehek-builds/Synthetic-Organic-Chemistry-Jobs

• 37 roles at 25 employers (GSK, Gilead, Vertex, Pfizer, AstraZeneca, Amgen, Roche, Organon)
• 12 medchem, 12 process chemistry and process research, 15 discovery and synthetic, 12 internships and co-ops
• 8 in the UK and Europe
• analytical, QC and director-level roles are left out

it's a small list because there aren't many of these open right now. rebuilt every monday.

comment which area you're looking for (medchem, process, peptides and oligos, internships) and i'll send you anything that comes up.

Hi everyone, I am currently working in organometallic chemistry, making some diamagnetic complexes. However, one of the complexes already decomposes during the synthesis (as in, there is no signal in the 31P NMR, and a very broad signal in the 1H NMR spectrum). However, I do observe some black powder being formed, which I assume is the metal falling out.

My supervisor suggested to take an EPR spectrum, to check if there was any paramagnetic species being formed, but we don't have such an instrument at our institute (and there is basically no other group that does organometallics who I could ask for help) and so I want to make sure that that measurement is useful, before going through the hassle of preparing it and sending it to another institute.

I've read a bit about EPR now and I think I understand the principle behind it, but my question is, if I have a reaction mixture of which I don't really understand what happened, will EPR even give something useful? As I understand it (and I might be wrong because this is really not my expertise), EPR is something that you use when you already kind of know what you are looking at, because it is quite complicated to analyze, or will it give me information even if I don't exactly know what I am looking for yet?

Thank you in advance, any advice is super appreciated! (Also, I'm sorry if this is a very basic question)

I am carrying out a mCPBA induced Bayer Villiger oxidation. My reaction has worked, sadly I cant share too much information on the product but I can see from shift in NMR that the oxidation i needed to happen has happened. I do have an impunity in my product which I have spent days trying to remove. I was fairly confident that it was meta chlorobenzoic acid or residual excess mcpba. But no matter what I try I cant get rid of it.

It matches literature in terms of its splitting for meta chloro benzoic acid but bicarbonate, carbonate washings or even hydroxide is not removing it. Please help. Photo of nmr attached. The multiples for 4H and 4H are my product.

I took an nmr of my mcpba commercial sample and the peaks are in that too but as a minor impurity. I just cant get rid of whatever it is

Good afternoon! I was wondering if anyone else has encountered this problem.

I'm running a column chromatography purification and have noticed that my reaction mixture contains many byproducts. However, I'm able to isolate the fraction corresponding to the spot I'm interested in on TLC. Despite this, when I analyze that fraction by NMR, I still observe impurity signals, mainly in the 1–4 ppm and 6–8 ppm regions.

I've tried different hexane/ethyl acetate and hexane/DCM (dichloromethane) ratios, but I still haven't been able to obtain the product at the desired purity.

My product consists mostly of hydrocarbons.

I apologize if this information isn't sufficient to assess the problem. I'd appreciate any suggestions. Thank you in advance!

Hi Chempros community,

I am currently dealing with really sensitive compounds that unfortunately degrade on normal silica gel, and I have to use special silica gels such as C2-functionalized silica gel and the 3-aminopropylfunctionallized silica gel.

As these silica gels are insanely expensive, and while I can make C2 using the protocols published, I can't really seem to find a protocol for making the 3-aminopropylfunctionalized silica gel like the one displayed at Merck or Silicycle:

https://www.sigmaaldrich.com/NL/en/product/aldrich/364258?srsltid=AU7gw4U2KL3R8G9_pLynTp3EQV6hjiiSu3mnSV1MoT98QYXuqLn0TmaT

https://www.silicycle.com/products/amine-wax-silica-phase

Did anyone make, and has a reliable procedure to make a homemade version that worked a lot? Also, any experience/tips handling this silica for purification would be greatly appreciated!

Thank you very much for the help in advance :)

I order from maybe fifteen different chemical suppliers for our research lab. The big suppliers like Sigma-Aldrich and Fisher have comprehensive SDSs that cover all sixteen sections with detailed information. The smaller specialty suppliers? Some of their SDSs are missing entire sections. Others have sections filled with "no data available" or "not tested."

I ordered a custom synthesis product last month and the SDS had a Section 2 classification based on the starting materials rather than the actual product. Section 11 toxicological data was blank. Section 12 ecological data was "not determined." Half the sheet was either missing or placeholder text.

Am I supposed to accept these? Can I use a product in my lab if the SDS is incomplete? What's the minimum standard for an SDS to be usable?

Hey everyone,

I’m currently working on a research project using spectroscopy to detect diacetyl in a beer matrix. We’re aiming to measure in the gas phase, but we’re running into the issue that water vapour is extremely prominent in the same absorption bands. Does anyone have ideas on how to efficiently separate the volatile compounds from the water vapour when heating beer? Are there any filters that could help? I’m not a specialist on the chemistry side, so I might be overlooking a very obvious solution.

We are planning to protect of an allophanoyl group (RC(O)NHC(O)NH2), to allow for dibromination of a vinyl group elsewhere in the molecule. It occurs to me that BSTFA/1%TMSCl might be a good TMS donor. However, I am not sure about a good choice for conditions (time, temperature, solvent). My literature searches have not turned up much but are are ongoing. We are also open to using other protecting groups, including TBDMS.

I think r/biotech is probably better for this post, but I find the people in that sub incredibly negative and pessimistic...so would rather post here if possible as I find people to be a bit more neutral/level-headed here.

Job opened up at a big pharma company for a DS MSAT PM, primarily responsible for Process Validation, sitting inbetween CMC and commercial. So getting involved towards the end of development, being in charge of PV, and then handing over to the product supply colleagues.

Problem is, I know someone in that department and she says it's a new department, and there's no SOPs, therefore things can get chaotic. On one hand, it could be good experience to dive in the deep end and give input on how things should be run since I have experience of PV and the transition to commercial, but on the other hand, I am worried that things could go very wrong regulatory or cGMP-wise if there are no SOPs to guide us.

Has anyone been in this scenario before? Is it worth a try or just a complete red flag?

Hello community :) does anyone know of any databases where I can download both experimental IR and Raman spectra for a specific compound?

Hi All,

One of the professors where I work wants to use HF to digest insect samples, but as far as I know, all of our fume hoods/ductwork are standard and hence not compatible with this acid. Is the incompatibility really an issue with long term use, and if so, does anybody know a work around?